Method and apparatus for adjusting threshold for determining HARQ feedback in NR V2X

Abstract

Provided are a method, performed by a first terminal, for adjusting a threshold for determining hybrid automatic repeat request (HARQ) feedback in a wireless communication system, and an apparatus for supporting the same. The method comprises the steps of: transmitting at least one piece of information to a second terminal; receiving, from the second terminal, at least one HARQ feedback in response to the at least one piece of information; determining an ACK or NACK with respect to the at least one HARQ feedback, based on the threshold; receiving, from the second terminal, an HARQ feedback transmission history of the second terminal; and adjusting the threshold, based on the HARQ feedback transmission history of the second terminal and information about the HARQ feedback determined by the first terminal.

What is claimed is: 
     
       1. A method performed by a first device in a wireless communication system, the method comprising:
 transmitting, to a second device, sidelink control information (SCI) on a physical sidelink control channel (PSCCH) for scheduling of a physical sidelink shared channel (PSSCH); 
 transmitting, to the second device, data on the PSSCH; 
 receiving, from the second device, information related to hybrid automatic repeat and request (HARQ) feedback in response to the transmission of the PSSCH; 
 decoding the HARQ feedback as an acknowledgement (ACK); and 
 determining the HARQ feedback as a negative acknowledgement (NACK) based on that a signal strength of the information related to the HARQ feedback is less than or equal to a first threshold, 
 wherein the first threshold is increased based on that a ratio that the first device determines NACK transmitted by the second device as ACK is higher than a second threshold, and 
 wherein the ratio is based on information related to a HARQ feedback transmission history of the second device, transmitted from the second device. 
 
     
     
       2. The method of  claim 1 , wherein the first threshold is adjusted based on a number of times that the first device determines the NACK transmitted by the second device as the ACK during a specific time period. 
     
     
       3. The method of  claim 1 , wherein the first threshold is adjusted based on a number of times that the first device determines that ACK transmitted by the second device as the NACK. 
     
     
       4. The method of  claim 1 , wherein the first threshold is adjusted based on a number of times that the first device determines that ACK transmitted by the second device as the NACK during a specific time period. 
     
     
       5. The method of  claim 1 , wherein the HARQ feedback transmission history of the second device is received from the second device based on a request of the first device. 
     
     
       6. The method of  claim 1 , wherein the HARQ feedback transmission history of the second device is periodically received from the second device. 
     
     
       7. The method of  claim 1 , wherein the first threshold is received from a base station or is pre-configured by the first device. 
     
     
       8. The method of  claim 1 , wherein the first threshold is adjusted based on an offset. 
     
     
       9. The method of  claim 1 , wherein the first threshold is adjusted between a maximum threshold and a minimum threshold. 
     
     
       10. A first device adapted to perform wireless communication, the first device comprising:
 at least one transceiver; 
 at least one processor; and 
 at least one memory connected to the at least one processor and storing instructions that, based on being executed, cause the first device to perform operations comprising: 
 transmitting, to a second device, sidelink control information (SCI) on a physical sidelink control channel (PSCCH) for scheduling of a physical sidelink shared channel (PSSCH); 
 transmitting, to the second device, data on the PSSCH; 
 receiving, from the second device, information related to hybrid automatic repeat and request (HARQ) feedback in response to the transmission of the PSSCH; 
 decoding the HARQ feedback as acknowledgement (ACK); and 
 determining the HARQ feedback as negative acknowledgement (NACK) based on that a signal strength of the information related to the HARQ feedback is less than or equal to a first threshold; 
 wherein the first threshold is increased based on that a ratio that the first device determines NACK transmitted by the second device as ACK is higher than a second threshold, and 
 wherein the ratio is based on information related to a HARQ feedback transmission history of the second device, transmitted from the second device. 
 
     
     
       11. A processing device adapted to control a first device, the processing device comprising:
 at least one processor; and 
 at least one memory connected to the at least one processor and storing instructions that, based on being executed, cause the first device to perform operations comprising: 
 transmitting, to a second device, sidelink control information (SCI) on a physical sidelink control channel (PSCCH) for scheduling of a physical sidelink shared channel (PSSCH); 
 transmitting, to the second device, data on the PSSCH; 
 receiving, from the second device, information related to hybrid automatic repeat and request (HARQ) feedback in response to the transmission of the PSSCH; 
 decoding the HARQ feedback as acknowledgement (ACK); and 
 determining the HARQ feedback as negative acknowledgement (NACK) based on that a signal strength of the information related to the HARQ feedback is less than or equal to a first threshold; 
 wherein the first threshold is increased based on that a ratio that the first device determines NACK transmitted by the second device as ACK is higher than a second threshold, and 
 wherein the ratio is based on information related to a HARQ feedback transmission history of the second device, transmitted from the second device.